If your options in Denali include a wildlife tour, by all means take it! We spent a remarkable time there a number of years ago and did two wildlife tours, one through the National Park Service and one through the hotel we stayed at. Both were wonderful - incredible scenery, bears, Dall sheep, ptarmigan, moose... The wildlife tours stop for almost every animal sighting (whether first spotted by the driver, guide or passengers on the bus). Denali is one of the most unspoiled national parks - fantastic place! Enjoy!